Protozoa Extra Information

Question 1

Plasmodium babesia

Answer 1

Apicomplexa
intermediate host = mammals and birds (multiplies in blood)
Definitive host = arthropod (multiplies in gut –> glands)

Question 2

Flagellates (4)

Answer 2

Giardia
Trichomonas
Trypanosoma
Leishmania

Question 3

Amoebozoa (3)

Answer 3

Entanomoeba
Acanthamoeba
Hartmanella

Question 4

Alveolates (3)

Answer 4

Cortical alveoli, flattened membrane-bound sacs
Apicomplexa
ciliates
dinoflagellates

Question 5

Apicomplexa

Answer 5

Under alveolates, have apical complex for cell invasion

Plasmodium, Sporozoans, coccida, microsporida

Question 6

Ciliates (2)

Answer 6

under alveolates
balantidium (GI)
Paramecium (non-pathogenic)

Question 7

Dinoflagellates

Answer 7

Under alveolates

photosynthetic algae, kill marine organisms, secrete toxins (found in fish, shellfish)

Question 8

Amoebic meningocephalitis

Answer 8

Clinical: Rapidly progressive, death 1 week
Patho: Free-living amoebas: Naegleria, Hartmanella, acanthomeoba infection from natural water swimming. Amoebas enter nose –> sinuses –> brain
Treatment: Amphoterecin and azoles

Question 9

Acanthomeoba

Answer 9

keratitis: contact lens solution made with contaminated H2)

Question 10

Neurological poisoning among laboratory workers

Answer 10

photosynthetic protozoa: dinofalgellates produce potetnt oxins, disease contracted by shellfish that ate toxins.

pfeisteria pscidida

Question 11

Balantium Coli

Answer 11

Disease similar to histolytic (amebic dysentery)

• find organism in stool
• large trophozoites with kidney shaped nucleus
• cysts are large and round

Question 12

Apicomplexa life cycle

Answer 12

Trophozytes –> multiple nuclear divisions without cytokinesis–> multinucleate SCHIZONTS –> schizogeny (cleavage) –> multiple uninucleate infective progeny released by lysis of host cell
Tachyzoites = fast dividing. Bradyzoites = slow dividing, Hypnozoites = semi-dormant

Forms with Sexual cyle:
Also produce macro gametocytes and micro gametocytes. In definitive host gametocytes –>meiosis–>haploid gametes –>fusion to form diploid zygote –>multiplies by schizogeny –> infectious for new intermediate hosts

Question 13

Plasmodium Babesia

Answer 13

Intermediate host (asexual) = mammal or bird
Definitive host (sexual) = arthropod vector - multiplies in gut spreads to salivary glands

Question 14

Toxoplasma Sarcocystis

Answer 14

Intermediate host (asexual) = rodent or ungulate - multiplies in gut, encysts in tissue, humans are accidental host
Definitive host (sexual) = carnivore - multiplies in gut shed in feces

Question 15

Cryptosporidium Isospora

Answer 15

Humans both intermediate and definitive host. Sexual and asexual cycles in gut, spread by fecal/oral route

Question 16

Mosquito cycle of plasmodium falciparum

Answer 16

gametocyte infectious to mosquito. they undergo meiosis to produce haploid gametes. Microgametocytes make flagella and motile gametes. In the gut these fertilize macro gametocytes to form zygotes (ookinetes) which invade the gut wall and for oocysts. Oocysts undergo sporogeny, producing multiple sporozoites which move to the mosquitos salivary glands.

Question 17

Babesia microti

Answer 17

reservoir in dogs, livestock. vector: ticks
Malaria-like endemic in NJ.
Diagnosis: blood smear, ring forms (rarely) cruciform

Question 18

Isospora belli

Answer 18

Fecal/oral, diarrhea, fever, abdominal pain. diagnosis by fecal smear

Question 19

Cyclospora cayetanensis

Answer 19

Fecal/oral, outbreaks from contaminated fruit/vegetables. Diarrhea, occasionally severe enough for hospitalization. Diagnose by cysts in acid-fast

Question 20

Sarcocystis

Answer 20

cycsts in raw/undercooked meat. Cycles between carnivores (intestinal form) and ungulates (muscle cysts). Encysts in muscle usually do not produce disease.
Diagnosis are serological.

Question 21

Microsporidia Life Cycle

Answer 21

Infectious form is the spore. Inside spore wall, cytosol of microsporidian is continuous with lumen of a long coiled polar filament. When spore contacts host cell, filament everts and pierces host cell plasma membrane. osmotic flow of water into spore forces cytoplasm of parasite through polar filament and into cytosol of host cell, where it develops into a trophozoite and then a schizont. Mitotic and meiotic divisions form zygotes, infectious spores are formed and released via lysis.
Immune-compromised people are at risk